In terminal SIV infection in macaques, lentivirus-infected leukocytes are numerous in SIV-specific infiltrates yet are rarely detected at inflammatory sites associated with opportunistic infections such as mycobacteriosis, SV40, and toxoplasmosis or in complete Freund's adjuvant (CFA)-induced skin granulomas. This refutes the theory that opportunistic infections during HIV/SIV infection serve as a stimulus for the recruitment of lentivirus-infected cells. However, during acute SIV-infection we have observed occasional animals with SIV-positive leukocytes associated with Pneumonyssus- and CFA-induced granulomas. We have also described virus-positive cells in the cellular infiltrates associated with pulmonary granulomas induced by tetrathyridia of Mesocestoides in a pigtailed macaque (Macaca nemestrina) during acute SIV infection. Our hypothesis is that SIV-infected leukocytes are able to traffic to inflammatory sites early in infection, but lose this ability late in disease.